fx(u,v) = 3*cos(u) + 5*cos(3*u) + 3*(cos(u)\
          +5*cos(3*u))*cos(v)/(2*sqrt(234+90*cos(2*u)))\
          -3*cos(6*u)*(sin(u)+5*sin(3*u))*sin(v)\
          /((2*sqrt(13+5*cos(2*u)))*sqrt(22+5*cos(2*u)+9*cos(12*u)))
fy(u,v) = 3*sin(u) + 5*sin(3*u) + 3*(sin(u)\
          +5*sin(3*u))*cos(v)/(2*sqrt(234+90*cos(2*u)))\
          +3*(5*cos(3*u)+cos(5*u)+cos(7*u)+5*cos(9*u))*sin(v)\
          /((4*sqrt(13+5*cos(2*u)))*sqrt(22+5*cos(2*u)+9*cos(12*u)))
fz(u,v) = 3*sin(6*u)\
          - sqrt(13+5*cos(2*u))*sin(v)/(2*sqrt(22+5*cos(2*u)+9*cos(12*u)))

set parametric
set samples 120
set ur [0:2*pi]
set vr [0:2*pi]
set xyplane 0        # 'set ticslevel 0' is obsolute
unset key
set style line 100 lt 1 lw 0.1 lc rgb "navy"
set pm3d hidden3d 100 depthorder
set palette defined ( 0 "navy", 1 "light-green")
set term pngcairo enh font "Times,8" size 480,280
set out "3dparam_knot.png"
splot fx(u,v),fy(u,v),fz(u,v) w pm3d